The Sonata battery is 10.4ah so will have 40 cells inside with 10 x 4 parallel groups to get 36v, the 4 cells in parallel give the ah of the battery so each cell is 2.6ah.
Samsung make the 2.6ah cell in a few versions 26F, 26H & 26J, there is little to choose between them and are much a like. My 26F was 13ah and lasted about 20 months before I saw capacity loss/range reducing for my use, 17a max current draw and up to 24mph. From new 45miles after 20 months about 30- 35 miles. The battery was used for best part of another year before I decided range was enough for me so the battery cells was broken up and I mad some 12v booster packs for my 36v batteries for 48v use.
2 years may possibly be the max the battery will give 95/100% range/mileage before you see decrease happening /capacity loss, it may be less with hilly Brighton.